thermostability

Cytochromes P450 are found throughout the biosphere in a wide range of environments, serving a multitude of physiological functions. The ubiquity of the P450 fold suggests that it has been co-opted by evolution many times, and likely presents a useful compromise between structural stability and conformational flexibility. The diversity of substrates metabolized and reactions catalyzed by P450s makes them attractive starting materials for use as biocatalysts of commercially useful reactions. However, process conditions impose different requirements on enzymes to those in which they have evolved naturally...

Fusion protein construction often requires peptide linkers for prolonged conformation, extended stability and enzyme activity. In this study a series of fusion between Thermotoga maritima lipase Tm1350 and Bacillus subtillis coat protein CotB, comprising of several peptide linkers, with different length, flexibility and orientations were constructed. Effects of temperature, pH and chemicals were examined, on the activity of displayed enzyme. The fusion protein with longer flexible linkers L9 [(GGGGS)4] and L7 (GGGGS-GGGGS-EAAAK-EAAAK-GGGGS-GGGGS) possess 1...

We have previously shown that incorporation of a second intradomain disulfide linkage into camelid VHH and human VH/VL single-domain antibodies confers increased thermostability. Here, we explored the effects of introducing an additional disulfide linkage, formed between Cys48 and Cys64 (Kabat numbering), into a phage-displayed synthetic human VL library. In comparison to an identical library bearing only the highly conserved Cys23-Cys88 disulfide linkage, the disulfide-stabilized VL library tolerated a similar degree of randomization but retained a higher level of functional diversity after selection with protein L...

The eIF2α kinase activity of the heme-regulated inhibitor (HRI) is regulated by heme which makes it a unique member of the family of eIF2α kinases. Since heme concentrations create an equilibrium for the kinase to be active/inactive, it becomes important to study the heme binding effects upon the kinase and understanding its mechanism of functionality. In the present study, we report the thermostability achieved by the catalytic kinase domain of HRI (HRI.CKD) upon ligand (heme) binding. Our CD data demonstrates that the HRI...

The gene (1488-bp) encoding a novel GH10 endo-β-1,4-xylanase (XylM) consisting of an N-terminal catalytic GH10 domain and a C-terminal ricin-type β-trefoil lectin domain-like (RICIN) domain was identified from Luteimicrobium xylanilyticum HY-24. The GH10 domain of XylM was 72% identical to that of Micromonospora lupini endo-β-1,4-xylanase and the RICIN domain was 67% identical to that of Actinospica robiniae hypothetical protein. The recombinant enzyme (rXylM: 49kDa) exhibited maximum activity toward beechwood xylan at 65°C and pH 6...

Although many models have been developed to guide the design and implementation of DNA tile-based self-assembly systems with increasing complexity, the fundamental assumptions of the models have not been thoroughly tested. To expand the quantitative understanding of DNA tile-based self-assembly and to test the fundamental assumptions of self-assembly models, we investigated DNA tile attachment to preformed "multi-tile" arrays in real time, and obtained the thermodynamic and kinetic parameters of single tile attachment in various sticky end association scenarios...

Understanding the chemical and physical interactions at the interface of protein surfaces and inorganic crystals has important implications in the advancement of immobilized enzyme catalysis. Recently, enzyme-inorganic hybrid complexes have been demonstrated as effective materials for enzyme-immobilization. The precipitation of phosphate nanocrystals in the presence of enzymes creates enzyme-Cu3(PO4)2-3H2O particles with high surface-to-volume ratios, enhanced activity, and increased stability. Here, we begin to develop a mechanistic understanding of enzyme loading in such complexes...

Visceral leishmaniasis (VL) is a fatal form of leishmaniasis which affects 70 countries, worldwide. Increasing drug resistance, HIV co-infection, and poor health system require operative vaccination strategy to control the VL transmission dynamics. Therefore, a holistic approach is needed to generate T and B memory cells to mediate long-term immunity against VL infection. Consequently, immunoinformatics approach was applied to design Leishmania secretory protein based multi-epitope subunit vaccine construct consisting of B and T cell epitopes...

Enzymatic saccharification of lignocellulosic biomass has been widely studied. Mainly endoglucanases were found to be a prerequisite for the quick initial biomass liquefaction. In the present study, Pichia pastoris was used as a host for the heterologous expression of a Sclerotinia sclerotiorum GH45 endoglucanase, Endo2. The recombinant plasmid pPICZαA was used to transform Pichia pastoris. Pichia culture supernatants expressing the recombinant Endo2 (rEndo2) were used for the purification and biochemical characterization of this enzyme...

Trehalose has important applications in the food industry and pharmaceutical manufacturing. The thermostable enzyme trehalose synthase from Thermobaculum terrenum (TtTS) catalyzes the reversible interconversion of maltose and trehalose. Here, we investigated the structural characteristics of TtTS in complex with the inhibitor TriS. TtTS exhibits the typical three domain glycoside hydrolase family 13 structure. The catalytic cleft consists of Asp202-Glu244-Asp310 and various conserved substrate-binding residues...

Sulfur mustard (SM) can be hydrolyzed by haloalkane dehalogenases such as DhaA, LinB and DmbA. However, the low resistance to the elevated temperatures limited the practical application of haloalkane dehalogenases. Here we reported a new thermotolerant dehalogenase FM2382 from Fulvimarina manganoxydans sp. nov. 8047. The specific activity of FM2382 to SM is 0.6 U/mg. FM2382 possessed high heat stability (45 °C) in slight alkali environment (pH 7.5) and retained approximately 50% activity after incubation at 70 °C for 40 min...

Functional screening of metagenomic libraries is an important tool for the discovery of new molecules. The metabolic diversity of microorganisms enables survival in harsh environments and is related to the production of enzymes. In this study, we identified a protease-producing clone from a metagenomic library derived from mangrove sediment. The protease was purified by ammonium sulphate precipitation and gel filtration chromatography, with a yield of 77.27% and a specific activity of 8.57 U μg(-1) . It had a molecular weight of approximately 70 kDa...

A group of small molecules that stabilize proteins against high hydrostatic pressure has been classified as piezolytes, a subset of stabilizing cosolutes. This distinction would imply that piezolytes counteract the effects of high hydrostatic pressure through effects on the volumetric properties of the protein. The purpose of this study was to determine if cosolutes proposed to be piezolytes have an effect on the volumetric properties of proteins through direct experimental measurements of volume changes upon unfolding of model proteins lysozyme and ribonuclease A, in solutions containing varying cosolute concentrations...

Byproducts from quinoa are not yet well explored sources of hemicellulose or products thereof. In this work, xylan from milled quinoa stalks was retrieved to 66% recovery by akaline extraction using 0.5 M NaOH at 80°C, followed by ethanol precipitation. The isolated polymer eluted as a single peak in SEC with a molecular weight >700 kDa. Analysis by FT-IR and NMR, combined with acid hydrolysis to monomers, showed that the polymer was built of a backbone of β-(1,4) linked xylose residues that were substituted by 4-O-methylglucuronic acids, arabinose and galactose in an approximate molar ratio of 114:23:5:1...

The long-standing problem of achieving high activity of a thermophilic enzyme at low temperatures and short reaction times with little tradeoff in thermostability has been solved by directed evolution, an alcohol dehydrogenase found in hot springs serving as the catalyst in enantioselective ketone reductions.

Increasing the thermostability of amorphous materials has been a long journey to improve their properties. The metastable nature of chalcogenide glasses limits their practical applications as an amorphous semiconductor in photovoltaic performance. Here, we report the formation and physical properties of ultrastable amorphous Sb2Se3 with an enhanced thermal stability compared to amorphous Sb2Se3 (∆Tx= 17 K). By in situ high temperature-high energy synchrotron X-ray diffraction, the difference in structure relaxation between ordinary and ultrastable amorphous Sb2Se3 was manifested by local structure evolution...

The carbonic anhydrase superfamily (CA, EC 4.2.1.1) of metalloenzymes is present in all three domains of life (Eubacteria, Archaea, and Eukarya), being an interesting example of convergent/divergent evolution, with its seven families (α-, β-, γ-, δ-, ζ-, η-, and θ-CAs) described so far. CAs catalyse the simple, but physiologically crucial reaction of carbon dioxide hydration to bicarbonate and protons. Recently, our groups characterised the α-CA from the thermophilic bacterium, Sulfurihydrogenibium yellowstonense finding a very high catalytic activity for the CO2 hydration reaction (kcat = 9...

The combination of the hydrothermal method with in situ synthesis has been successfully employed to prepare a family of tetrazole-based energetic metal-organic frameworks (EMOFs) ([Ag(Mtta)]n, 1; [Cd5(Mtta)9]n, 2; [Pb3(bta)2(O)2(H2O)]n, 3; and [Pb(tztr)2(H2O)]n, 4) through [2 + 3] cycloaddition of azide anions and nitrile groups. All the synthesized EMOFs were characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis (EA), different scanning calorimetry (DSC), and thermogravimetry (TG)...

Xylanases catalyze the random hydrolysis of xylan backbone from plant biomass and thus, they have application in the production of biofuels, Kraft pulps biobleaching and feed industry. Here, xylanases derived from Orpinomyces sp. PC-2 were engineered guided by molecular dynamics methods to obtain more thermostable enzymes. Based on these models, 27 amino acid residues from the N-terminal were predicted to reduce protein stability and the impact of this removal was validated to two enzyme constructs: small xylanase Wild-Type (SWT) obtained from Wild-Type xylanase (WT) and small xylanase Mutant (SM2) generated from M2 mutant xylanase (V135A, A226T)...

Biliproteins have extended the spectral range of fluorescent proteins into the region of maximal transmission of most tissues and are favorable for multiplexing, but their application presents considerable challenges. Their fluorescence derives from open-chain tetrapyrrole chromophores which often require the introduction of dedicated reductases and lyases. In addition, their fluorescence yield generally decreases with increasing wavelengths and depends strongly on the state of the binding protein. We report fluorescent biliproteins, termed BDFPs, that are derived from the phycobilisome core subunit, ApcF2: this subunit is induced in the thermophilic cyanobacterium, Chroococcidiopsis thermalis, by far-red light and binds phycocyanobilin non-covalently...